Nowadays, wireless communication technologies have experienced great growth and are now rapidly gaining in popularity. As a result, many peripheral devices of computer system were developed according to wireless communication technologies, so that signals or data are transmitted between the peripheral devices and the host computer. Among the wireless peripheral devices, wireless keyboard, wireless mouse, wireless earphone, wireless microphone and the like are prevailing. When a wireless peripheral device is operated, a corresponding wireless signal receiver is employed for receiving the wireless signal delivered from the wireless peripheral device. Generally, the wireless signal receiver is connected to an extension slot of the host computer. Therefore, the signals generated from the wireless peripheral device can be transmitted to the host computer via the wireless signal receiver.
The common wireless communication protocols are usually operated in the bandwidth of for example 2.4 G Hz. Devices communicating by means a specified wireless technology run the risk of encountering interference in environments where other wireless technologies are in use. For reducing interference between wireless technologies sharing the 2.4 GHz spectrum, a so-called automatic frequency hopping method was developed. Frequency hopping devices can know which frequencies are occupied by other users of the band and then rapidly switched among other frequency channels.
In wireless transmission, packet error rate is a measure of discriminating whether the channel frequency has to be switched. A method of estimating the packet error rate caused by interference utilizes a radio frequency integrated circuit (RFIC) to detect the interference level, thereby discriminating whether the channel is encountering interference. However, if the wireless peripheral device is relatively far from the host computer, it is usually deemed that channel switching is necessary. As known, too frequent channel switching may increase power consumption.
Another method of discriminating whether the channel-switching is required utilizes a received signal strength indicator (RSSI) to indicate how strong a signal is at a receiver. RSSI is measured in each channel in order to specify a frequency channel being used in a wireless communication by another communication apparatus, and if specified, such a frequency channel is avoided based upon the measurement result. In a case that a wireless peripheral device employs a lower-level RFIC when taking cost into account, insufficient number of frequency channels are provided for performing channel-switching. Under this circumstance, the threshold value associated with each channel is so high that the packet lost rate is increased.
In views of the above-described disadvantages resulted from the prior art, the applicant keeps on carving unflaggingly to develop a channel switching method according to the present invention through wholehearted experience and research.